The conventional bicycle utilizes a wheel sprocket connected to the hub of the rear wheels, a pedal sprocket mounted between the front and rear wheels, and a drive chain connecting the two sprockets. Forced rotation of the pedal sprocket produces rotation of the wheel sprocket and thereby rotation of the rear wheel. A foot pedal projects laterally from each side of the pedal sprocket but radially spaced from the sprocket axis and 180.degree. from each other. The bicycle rider generates circular movement of the pedals around the pedal sprocket axis with his feet to produce rotative motion of the pedal sprocket and propulsion of the bicycle.
The degree of difficulty in pedaling the bicycle is dependent on many factors. For example, accellerating a bicycle from a stopped position or climbing a hill is far more difficult then simply maintaining a set speed on a level street. Where difficulty is a factor, it can be minimized by "gearing down", a term used herein to describe a relationship between the pedal sprocket and wheel sprocket whereby several turns of the pedal sprocket is required for a single turn of the wheel sprocket. The leverage that is produced in "gearing down" enables the force of the rider pushing against the pedals to have increased effectiveness. However, as the bicycle gains speed the rider will find it difficult to rotate his feet fast enough to keep up. Thus, where speed is an important factor, the rider will want to "gear up" i.e. a relationship whereby a single turn of the pedal sprocket will generate one or more turns of the wheel sprocket.
Whereas gear shifting mechanism has been developed to where bicycles having many gear positions are available, they all require a peddling power produced by a circular motion of the rider's feet. To produce the desired circular force, the rider goes through a series of movements wherein the pedal, from near its upper most position, is pushed forward, then forward and down, and then down and rearward, until the opposite pedal nears its upper most position and the same action is repeated with the opposite foot. Thigh, leg, back and arm muscles all come into play and although the rider's weight is a definite factor in helping to produce the circular force, it is only a factor and bicycling for any period of time is a strenuous exercise.
It is an object of the present invention to simplify the rider's movements in developing the force to propelthe bicycle. This is primarily accomplished with mechanism that also generates advantages that reduces the required force without the attendent reduction in speed capabilities.